Short report: A trend analysis of attitudes towards early diagnosis of dementia in Germany

Background Early detection of dementia provides numerous benefits for those living with dementia and their relatives and healthcare systems at large. Methods available for early diagnosis have improved significantly over the past years. Therefore, we examined whether support for offering an early diagnosis of dementia and willingness to pursue a respective early diagnosis have changed in Germany over the last decade. Method We compared findings from two representative telephone surveys conducted among older adults in Germany (≥ 60 years of age) in 2011 and 2022, assessing support for offering an early diagnosis of dementia and willingness to pursue a respective early diagnosis in a sample of n = 879 individuals (mean age: 72.9, range: 60–98 years, % female: 58.8). Group comparisons using Chi2- and t-tests and multivariable regression analyses were conducted, regressing support of an early diagnosis of dementia and willingness to pursue a respective early diagnosis on age, gender, education, employment status, belief in preventability of dementia and time of survey. Results Support for offering an early diagnosis of dementia was high both in 2011 (90.7%) and 2022 (79.2%), but declined over time (OR: .39; 95% CI: .25; .63). Willingness to pursue an early diagnosis of dementia declined from 70.7% to 60.1% in the same period (OR: .62; 95% CI: .45; .86). Belief in preventability of dementia was linked to support for offering an early diagnosis (OR: 1.88, 95% CI: 1.25; 2.83) and willingness to pursue an early diagnosis of dementia (OR: 1.52; 95% CI: 1.12; 2.07). Older participants less often supported offering an early diagnosis of dementia (OR: .97, 95% CI: .95; .99). Conclusion Support for offering an early diagnosis of dementia and willingness to pursue a respective diagnosis is high in the older German public, but lower than reported previously. Improving knowledge on modifiable risk factors and better understanding of individual motives underlying endorsement or refusal of an early diagnosis may increase acceptance in the general public.


Conclusion
Support for offering an early diagnosis of dementia and willingness to pursue a respective diagnosis is high in the older German public, but lower than reported previously. Improving knowledge on modifiable risk factors and better understanding of individual motives underlying endorsement or refusal of an early diagnosis may increase acceptance in the general public.

Background
Current estimates of people living with dementia are projected to increase from currently 55 million people worldwide up to 150 million in 2050 [1,2]. These estimates, however, only include those with a diagnosis of dementia. Diagnosis rates for dementia remain low, and globally, an estimated 75% of cases are undiagnosed, with numbers even higher in low-and middle-income countries [2]. With numbers of people living with dementia rising rapidly [3], importance of timely diagnosis of dementia has been emphasized by Alzheimer's Disease International and the World Health Organization, among others [4][5][6]. This includes the use of biomarkers such as assessing hippocampal atrophy using magnetic resonance imaging or decreased levels of Aβ42 and elevated levels of tau and phosphor-tau in cerebrospinal fluid in preclinical stages of dementia [7,8].
Early diagnosis of dementia can entail several advantages. First, knowledge of the underlying condition can relieve uncertainty and irritation on the side of relatives and caregivers when early signs, e.g. forgetfulness or loss of orientation, become apparent, thereby facilitating adjustment and reducing emotional stress on the side of caregivers [9]. Knowing the reason for changes in cognition and behavior can further relieve stress on the side of those affected, as they no longer have to make efforts to hide difficulties related to impaired functioning in daily life [10]. Receiving an early diagnosis of dementia enables the person with dementia and his or her next ones to access care and make precautions for the future, e.g. arrangements of care and living situation, legal guardianship etc. [4,11]. Patient organizations like the German Alzheimer's Association (Deutsche Alzheimer Gesellschaft) openly favor early visits to memory clinics or general practitioners (GPs) when noticing first symptoms of cognitive decline to pursue an early diagnosis of dementia [10].
On the other hand, ethical considerations including lack of available cure for dementia and the risk of psychological burden on the side of persons living with dementia, e.g. depressive symptoms, fear or suicidal ideation, are often raised as arguments against an early diagnosis [12]. Further, fear of losing control and independence, stigmatization, loss of social relationships and quality of life can raise fear on the side of older adults considering an early diagnosis of dementia [4,10].
For successful implementation in primary care, knowledge on acceptance and public attitudes towards early diagnosis of dementia is crucial. Acceptance of regular screening for Alzheimer's disease in primary care has been reported high (71.2%) in a study conducted among older adults in Germany (60-80 years, mean age: 68.3 years; [13]). Similarly, a populationbased survey conducted a decade ago among adults aged 18 years and older in Germany revealed high levels of support, with 87.9% supporting offering a diagnosis and 68.6% willing to pursue a diagnosis themselves [14]. However, these studies were based on convenience sampling or conducted several years ago. Against this background, we investigated time trends in attitudes towards early diagnosis of dementia and preferred sources of professional help for dementia in the older general population in Germany. We therefore assessed support for offering an early diagnosis of dementia and willingness to pursue a respective early diagnosis in a population-based sample, applying a similar methodology and assessments as used by Luck et al. [14] to allow for direct comparisons over time.

Recruitment and study population
We used data from two independent population-based surveys, conducted in 2011 and 2022, respectively. For both surveys, computer-assisted telephone interviews were conducted by USUMA GmbH, a German market and social research institute with expertise in healthrelated research. Participants were recruited applying a multi-stage random digit dialing procedure, using the Association of German Market and Social Research Agency's (ADM) sample base, allowing for the inclusion of registered and non-registered telephone numbers from the German resident population. Telephone numbers were drawn proportionally to the respective German population structure in 2011 and 2022, stratified regionally according to district sizes. The Kish-Selection-Grid was applied within households to randomly select the target person to be interviewed within households (aged 18 or older in 2011 or 60 and older in 2022). A researcher from Leipzig University trained interviewers of USUMA GmbH for both surveys and interviewers were randomly monitored for quality control. The study was carried out in accordance with the principles of the Declaration of Helsinki in its revised version from 2000. The Ethics Committee of the Medical Faculty of the University of Leipzig approved the study (ref.: 587/21-ek). Interviewers informed participants verbally about the study at the beginning of the telephone interviews. Participants then provided oral consent, documented electronically by USUMA GmbH.
In the 2011-survey, 25,027 telephone numbers were contacted, identifying 5,897 eligible individuals. Among these, n = 551 (9.3%) individuals could not be reached, refused to be interviewed (n = 2,241, 38.0%) or discontinued the interview (n = 102, 1.7%), leading to a sample of 3,003 complete telephone interviews. Questions on support for offering an early diagnosis of dementia, willingness to pursue a respective diagnosis and preferred sources of support were asked in every third interview, therefore, the final analysis sample contained 1,002 individuals. For the 2022-survey, 1,067 individuals were initially selected. Excluding individuals who could not be reached (n = 244, 22.9%) or refused participation (n = 320, 30.0%), the final sample included n = 503 respondents. The two surveys included adults of different age groups (2011: adults aged 18 years and older; 2022: adults aged 60 years and older). To increase comparability, only adults aged � 60 years in the 2011-survey were included in the present study. The final study sample included n = 879 individuals, n = 376 interviewed in 2011 and n = 503 interviewed in 2022.

Instruments
For the present study, we used information assessed in both surveys using standardized questionnaires, i.e. participants' gender, age, country of birth, education and occupational status (employed vs. retired, unemployed or homemaker). Education was assessed using the Comparative Analysis of Social Mobility in Industrial Nations (CASMIN)-classification, comprising information on professional and vocational education [15]. Participants were then asked about their support of offering an early diagnosis of dementia ("Do you think that early detection of dementia should be offered?", response options: yes, no). Further, we assessed willingness to pursue a respective early diagnosis ("Would you be willing to be examined for an early diagnosis of dementia?", response options: in all cases, more likely, undecided, less likely, no). Participants' belief in the preventability of dementia was assessed asking "Do you think that dementia could be prevented?" (response options: yes, no). Lastly, participants were asked about preferred sources of support for dementia diagnosis and care ("What would be your first source of professional help?", response options: general practitioner, neurologist, psychiatrist, specialized services like memory clinics, other, I don't know).

Statistical analyses
Group comparisons were run using Chi 2and t-tests as appropriate. We assessed factors associated with support of offering an early diagnosis of dementia and willingness to pursue a respective early diagnosis using multivariable logistic regression analyses. Response options for willingness to pursue an early diagnosis of dementia were dichotomized, with options "more likely" and "in all cases" indicating the will to pursue an early diagnosis of dementia, and options "undecided", "less likely" and "no" indicating refusal. Support for offering an early diagnosis of dementia and willingness to pursue a respective early diagnosis was regressed on time, gender, age, education, employment status and belief that dementia could be prevented. All analyses were conducted using Stata 16.0 SE (StataCorp, College Station, TX, USA) and an alpha-level of 0.05 (two-tailed) was chosen to indicate significance. Table 1 presents sociodemographic information on the two samples, assessed in 2011 and 2022.

Sample description
Participants in the 2022-survey were more often female (p = .005) and had higher levels of education (p < .001) than participants in the 2011-survey. On average, participants in the 2022-survey were older than those participating in 2011 (p < .001). Belief that dementia can be prevented was higher in 2022 than in 2011 (p = .002). The two samples did not differ significantly with regard to employment status (p = .124) or country of birth (p = .948).
In  Education assessed according to CASMIN; missing: information: education, 2011-sample: .5% (n = 2), 2022-sample: .6% (n = 3); country of birth, 2022-sample: .2% (n = 1); belief in preventability of dementia, 2022-sample: 11.5% (n = 58). https://doi.org/10.1371/journal.pone.0272896.t001 Attitudes towards an early diagnosis of dementia Support for offering an early diagnosis of dementia was high in both samples, but lower in 2022 than in 2011 (79.2% vs. 90.7%, Table 2). Asked whether they would be willing to pursue a respective early diagnosis of dementia themselves, participants in the 2022-survey less often endorsed the options "more likely" or "in all cases" than those in the 2011-survey (2022: 60.1%; 2011: 70.7%; p = .001). Table 3 describes factors associated with support for offering an early diagnosis of dementia, assessed using multivariable regression analyses. Older participants less often supported offering an early diagnosis (OR: .97, 95% CI: .95; .99), while belief in preventability of dementia was linked to support for offering an early diagnosis (OR: 1.88, 95% CI: 1.25; 2.83). Respondents in the 2022-survey less often favored offering an early diagnosis for dementia than respondents in 2011 (OR: .39, 95% CI: .25; .63). Support for offering an early diagnosis of dementia was not linked to gender, education or employment status.
Factors linked to willingness to pursue an early diagnosis of dementia, assessed using multivariable logistic regression analyses, are provided in Table 4. In 2022, respondents less often stated wanting to pursue an early diagnosis of dementia (OR: .62, 95% CI: .45; .86). The wish to pursue an early diagnosis was not linked to age, gender, education or employment status. Believing that dementia can be prevented was associated with the wish to pursue an early diagnosis of dementia (OR: 1.52, 95% CI: 1.12; 2.07).

Discussion
Our primary aim was to assess time trends in attitudes towards early diagnosis of dementia in the older general population in Germany, drawing upon data from two population-based surveys conducted in 2011 and 2022 using comparable methodology and questionnaires. A majority of participants was in favor of offering an early diagnosis for dementia, however, the respective proportion declined from 90.7% in 2011 to 79.2% in 2022. Comparable trends were observed for the wish to pursue an early diagnosis for dementia, with lower rates in 2022 than in 2011 (60.1% vs. 70.7%). Our results might point towards greater fear of or skepticism towards the benefits of early diagnosis than reported a decade ago. Support for offering an early diagnosis of dementia was not linked to gender, education or employment status. Higher age was linked to less support for offering an early diagnosis for dementia, comparable to findings from a previous study from Germany, reporting that higher age was linked to greater skepticism towards an early diagnosis for dementia [16]. Willingness to pursue an early diagnosis of dementia was not explained by differences in age, gender, education or employment status, as indicated by multivariable regression analyses. Believing that dementia can be prevented was linked to support for offering an early diagnosis of dementia and willingness to pursue a respective diagnosis. Similar findings were reported by Hajek and König, who found that belief in preventability was linked to less fear of dementia in a population-based German sample of older adults [17].
Most older adults in our samples would prefer their attending GP as professional helper regarding dementia, with similar estimates across time. Only small numbers of respondents named other professions, e.g. neurologists, as preferred sources of professional help. This is in line with findings from several national and multinational studies, highlighting that GPs often constitute the first contact of patients regarding dementia diagnosis and care [18][19][20]. As most older people see their attending GP on a regular basis, often over extensive periods of time, GPs play an important role in detecting first signs of dementia and informing patients and relatives on further steps to be taken regarding treatment and care [21], as emphasized in the German National Dementia Strategy ("Nationale Demenzstrategie"; [22]). Our findings therefore illustrate the importance of enabling GPs to detect early signs of dementia in primary care and to inform people living with dementia and their families about further medical and legal steps to be taken. However, the small proportion of older adults naming memory clinics as preferred sources of support demands attention. Although the network of memory clinics as specialized institutions for the diagnosis of dementia and prodromal stages of disease has been expanding rapidly during the last decade, the proportion of older adults considering visits to a memory clinic declined by more than 50% in our study. Future studies are warranted to investigate awareness of memory clinics and their respective services and reasons for acceptance or refusal in the older general population in Germany. Respective investigations might inform actors in health policy and health care systems to make the best use of available resources in the long run. Our findings suggest that strengthening knowledge on modifiable risk factors for dementia and opportunities to prevent or delay disease onset might increase support for offering an early diagnosis of dementia and willingness to be diagnosed accordingly. Further analyses revealed that support for offering an early diagnosis of dementia was linked to better knowledge of risk and protective factors for disease in the 2022-sample, and better knowledge of risk and protective factors predicted greater openness towards interventions for brain health [23]. Providing older adults with information and guidelines on how to preserve cognitive function in older age by means of a healthy lifestyle (e.g. management of cardiovascular risk factors, physical, social and cognitive activity, healthy diet) might strengthen belief that cognitive decline and dementia can be subject to intervention and preventive approaches. Respective efforts might in turn foster support of early diagnosis of the condition. On the other hand, recent studies have identified a shift in public and medical discourses about dementia, with strong focus on individual means of risk modification, running the risk of shifting responsibility for the condition one-sidedly on the individuals affected [24,25]. Over-emphasizing the potential of prevention might lead to increased fear or shame in older adults if they experience signs of cognitive decline, possibly making them more reluctant to pursue an early diagnosis of dementia. Since, however, we did not directly assess fear of dementia or perceived individual disease risk in our study, this line of thought should be interpreted with caution. Future studies assessing reasons for support or refusal of an early diagnosis of dementia in older adults are highly warranted. These could additionally assess further covariates possibly linked to attitudes towards an early diagnosis of dementia, e.g. perceived impact of a diagnosis on one's future, beliefs about and attitudes towards people living with dementia.
Belief that dementia can be prevented was higher in 2022 than in 2011. While a systematic review on dementia literacy in population-based samples from 2018 found that an overall 48% of respondents thought that dementia is not preventable [26], more recent studies indicate greater belief in the possibility of dementia risk reduction, with respective values ranging from 64.5% [27] to 70% [28], which is in line with our findings. Knowledge of specific risk and protective factors for dementia in the 2022-survey are described in detail elsewhere [23].

Strengths and limitations
Certain limitations need to be considered when interpreting our findings. We were not able to assess possible associations of marital status with support of an early diagnosis of dementia or willingness to pursue an early diagnosis, as this information was not collected during the 2011-survey. Caring roles and responsibilities for family members, especially spouses or partners, might likely influence attitudes towards provision and use of early diagnosis of dementia. Moreover, we cannot make statements about possible reasons underlying support of an early diagnosis of dementia or willingness to be diagnosed accordingly, as this information was not assessed in the two surveys. Questions assessing e.g. fear of dementia might provide further insights on why older adults endorse or refuse an early diagnosis of dementia. Lastly, our survey investigated belief in preventability of dementia rather broadly by asking a closed-ended question, the response options being "yes" and "no". It needs to be pointed out that individual disease risk is not fully amendable to change, however, to enhance comprehensibility, we decided to phrase the respective question as plain as possible. This study uses data from two population-based surveys conducted using similar questionnaires and sampling technique, allowing for the investigation of time trends regarding support of an early diagnosis of dementia and willingness to pursue a respective early diagnosis in the older general population in Germany. Our findings might therefore provide insights that are more generalizable to different populations than e.g. studies using convenience sampling. Further, the use of two independent samples should make our results more robust against non-random sample attrition and selection effects often encountered in panel data studies [29]. Despite advances in available means for early detection of dementia and development of risk assessment tools, evidence on their acceptance in the general public is currently rare [30]. Knowledge on support of an early diagnosis of dementia in the general public is of critical importance, as approval of screening procedures might likely influence processes of decision making and improve adherence to agreements regarding treatment and care in older adults [31].

Conclusion
By including data from a survey conducted a decade ago, we were able to identify trends in attitudes towards early diagnosis for dementia in the older general population. Support of and willingness to pursue an early diagnosis of dementia remain high in older German adults, although with slight decreases during the last decade. Improving knowledge on modifiable risk and protective factors for dementia, but also further investigations on what motivates older adults to endorse or refuse a respective diagnosis might help increase public support of early diagnosis of dementia. Nevertheless, ethical considerations regarding dementia diagnosis and disclosure of results as well as different needs and preferences of older adults need to be taken into account when discussing means of early diagnosis of dementia.